Vanda roxburghii chloroform extract as a potential source of polyphenols with antioxidant and cholinesterase inhibitory activities: identification of a strong phenolic antioxidant.

Md Nasim Uddin,Md Jalal Uddin,Md Josim Uddin,A H M K Alam,Golam Sadik,Rejina Afrin,Aziz Abdur Rahman

doi:10.1186/s12906-015-0728-y

Md Nasim Uddin, Md Jalal Uddin + Show 5 more

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https://doi.org/10.1186/s12906-015-0728-y

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Abstract

BackgroundAlzheimer’s disease (AD) is a progressively developing neurodegenerative disorder of the brain in the elderly people. Vanda roxburghii Rbr. root has been used traditionally in Bangladesh as tonic to brain and in the treatment of nervous system disorders including AD. Therefore, we aimed to investigate the cholinesterase inhibitory activities and antioxidant properties of the extracts from V. roxburghii.MethodsThe crude methanol extract from the roots of plant was sequentially fractionated with petroleum ether, chloroform, ethylacetate and water to yield their corresponding extracts. The extracts were assessed for acetylcholinesterase and butyrylcholinesterase inhibitory activity by modified Ellman method and antioxidant property by several assays including ferric reducing antioxidant power, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and hydroxyl radical, and inhibition of lipid peroxidation. Endogenous substances in the extracts were analyzed by the standard phytochemical methods and active compound was isolated by the chromatographic methods.ResultsChloroform extract was shown to demonstrate strong ferric-reducing antioxidant power and scavenging activity against DPPH and hydroxyl free radicals when compared with the other extracts and the reference standard catechin. The antioxidant effect was further verified by inhibition of lipid peroxidation in rat brain homogenates. Likewise, the chloroform extract exhibited the highest inhibition against both the acetylcholinesterase and butyrylcholinesterase enzymes with IC50 values of 221.13 and 82.51 μg/ml, respectively. Phytochemical screening revealed a large amount of phenolics and flavonoids in the chloroform extract. Bioactivity guided separation techniques led to the isolation of a strong antioxidant from the chloroform extract and its structure was determined as gigantol on the basis of spectral studies.ConclusionThese results suggest that the chloroform extract of V. roxburghii, possibly due to its phenolic compounds, exert potential antioxidant and cholinesterase inhibitory activities, which may be useful in the treatment of AD.

Highlights

Alzheimer’s disease (AD) is a progressively developing neurodegenerative disorder of the brain in the elderly people
The practice of traditional medicine has described a wide range of plants and herbs which may be used in the treatment of AD
We evaluated the different extracts of V. roxburghii for cholinesterase inhibitory and antioxidant activities

Summary

Introduction

Alzheimer’s disease (AD) is a progressively developing neurodegenerative disorder of the brain in the elderly people. Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder in the elderly people with symptoms of memory loss, cognition and behavioral abnormalities. Only three cholinesterase inhibitors (ChEI) such as donepezil, galantamine and rivastigmine has been approved by the US Food and Drug Administration (FDA) to treat AD [11, 12]. These drugs are effective only in mild to moderate AD and do not reverse the disease progression. It has become a necessity to develop the new ChE inhibitors that are pharmacologically safe, cost effective and immediately available with minimal side effects

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